An unknown substance can be identified by

Write insoluble or soluble solution for the following mixtores 1 2 3 4 5

dimaraw [331]

Gasoline in water = insoluble

acetone in nail polished = soluble

salt in alcohol = soluble

oil in vinegar = insoluble

tawas in water = soluble...

Sorry if i am incorrect......

6 0

2 years ago

Ethanol (c2h5oh) melts at -114Â°c. the enthalpy of fusion is 5.02 kj/mol. the specific heats of solid and liquid ethanol are 0.9

Nimfa-mama [501]

Answer: 4.18925 kJ heat is needed to convert 25.0 g of solid ethanol at -135 °C to liquid ethanol at -50°C.

Explanation:

Temperature of Solid $C_2H_5OH=-135^oC=138 K(0^oC=273K)$

Melting temperature of Solid $C_2H_5OH=114^oC=159 K$

Temperature of liquid $C_2H_5OH=-50^oC=223K$

Specific heats of solid ethanol = 0.97 J/gK

Specific heats of liquid ethanol = 2.3 J/gK

Heat required to melt the the 25 g solid $C_2H_5OH$ at 159 K

$\Delta T_1$ = 159 K - 138 K = 21 K

$Q_1=mc\Delta T= 25\times 0.97J/gK\times 21 K=509.25 J$

Heat required to melt and raise the temperature of $C_2H_5OH$ upto 223 K

$\Delta T_2$ = 223 K - 159 K = 64 K

$Q_2=mc\Delta T= 25\times 2.3J/gK\times 64 K=3680 J$

Total heat to convert solid ethanol to liquid ethanol at given temperature :

$Q_1+Q_2=509.25 J+3680 J=4189.25 J=4.18925 kJ$ (1kJ=1000J)

Hence, 4.18925 kJ of heat will be required to convert 25.0 g of solid ethanol at -135 °C to liquid ethanol at -50°C.

6 0

2 years ago

Explain why the atomic radius of fluorine is smaller than that of lithium

Sladkaya [172]

1. Common knowledge : Go to the right of periodic table, the atomic radius is decreasing

2. Flurine has 9 protons and lithium has 3 protons. you know that the electron is attracted with the centre of the atom, that's why more proton, more 'energy' that attract to the centre and that's why it make the shape of the atom is smaller

4 0

2 years ago

An aqueous solution contains 1.00 g/L of a derivative of the detergent laurel alcohol. The osmotic pressure of this solution is

iVinArrow [24]

Answer:

mm = 1043.33 g/mol

Explanation:

osmotic pressure (π):

π = CbRT

∴ π = 17.8 torr = 0.0234 atm

∴ Cb: solute concentration

∴ T = 25°C = 298 K

∴ R = 0.082 atm.L/K.mol

⇒ Cb = π/RT

⇒ Cb = (0.0234 atm)/((0.082 atm.L/K.mol)(298 K))

⇒ Cb = 9.585 E-4 mol/L

molar mass (mm):

⇒ mm = (1.00 g/L)(L/9.585 E-4 mol)

⇒ mm = 1043.33 g/mol

7 0

3 years ago

Chalcopyrite is an ore with the composition cufes2. what is the percentage of iron in a 39.6 g sample of this ore? answer in uni

iren2701 [21]

Well it depends on percentage by what, but I'll just assume that it's percentage by mass. For this, we look at the atomic masses of the elements present in the compound. Cu has an atomic mass of 63.546 amu Fe has 55.845 amu and S has 36.065 amu Since there are 2 molecules of Sulfur for each one of Cu and Fe, we'll multiply the Sulfur atomic weight by 2 to obtain 72.13 amu So we have not established the mass of the compound in amus 63.546 + 55.845 + 72.13 = 191.521 That is the atomic mass of Chalcopyrite. and Iron's atomic mass is 55.845 So to get the percentage, or fraction of iron, we take 55.845 / 191.521 Which comes out to 29.15% by mass Mass of the sample is not needed for this calculation, but since the question mentions it I would go ahead and check if the question isn't also asking for the mass of Iron in the sample as well, in which case you just find the 29.15% of 67.7g

5 0

3 years ago